Method of and system for mobile surveillance and event recording

ABSTRACT

A data-encoding system includes a source of unencoded data, and a first encoder interoperably coupled to the source, wherein the first encoder is adapted to receive the unencoded data, encode the unencoded data, and output encoded data at a first data rate. The data encoding system further includes a second encoder interoperably coupled to the source, wherein the second encoder is adapted to receive the unencoded data, encode the unencoded data, and output encoded data at a second data rate in which the second data rate exceeds the first data rate. This Abstract is provided to comply with rules requiring an Abstract that allows a searcher or other reader to quickly ascertain subject matter of the technical disclosure. This Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from, and incorporates byreference the entire disclosure of, U.S. Provisional Patent ApplicationNo. 60/617,988, filed on Oct. 12, 2004.

BACKGROUND OF THE INVENTION

This invention is directed to a video surveillance system, and inparticular, by way of example and not limitation, to a videosurveillance system adapted to be mounted in a law enforcement vehiclefor producing a permanent digital evidentiary record, on a multi-mediadisc, of a traffic stop or other event and incidents occurring after asuspect's vehicle has been stopped.

In law enforcement, a reliable witness that is incapable of perjury isneeded to substantiate actions taken by a law enforcement officer and toprotect the officer against false allegations by persons involved in anincident. An excellent witness of this type is a video recording of theincident, now widely used in traffic stops and criminal investigations,which can be reviewed after the incident and archived. By recording theincident first-hand as it actually happens, video recordings serve toeliminate conflicting individual interpretations of the incident andfacilitate effective and efficient law enforcement.

Vehicle-mounted video cameras to make video records of an incident orscene external to the law enforcement vehicle are well known in the art.For example, U.S. Pat. No. 4,949,186 to Peterson discloses avehicle-mounted system in which a video-cassette recorder is housed in avault located in the trunk of a patrol car. U.S. Pat. No. 5,677,979 toSquicciarini et al discloses a video surveillance system whichintegrates the outputs of a video camera, a radar unit, a remotecontrol, and a wireless microphone to produce a comprehensive videorecording of an incident from its beginning to the end. This system alsouses a video cassette recorder to capture the incident on videotape.However, VHS and digital video tapes are bulky, requiring considerablespace for storage, are susceptible to damage, and degrade over time.Additionally, the data on tapes may only be accessed sequentially.

SUMMARY OF THE INVENTION

A video-data chapter segmentation method includes monitoring for atleast one external start trigger, and responsive to detection of atleast one of the at least one external start trigger, creating a chapterstart point at a point in the video data corresponding to a specifiedtime preceding the at least one detected external start trigger. Themethod further includes initiating recording of the video data beginningat the point in the video data and monitoring for at least one stoptrigger. The method still further includes responsive to detection of atleast one of the at least one stop trigger, creating a chapter stoppoint at a point in the data corresponding to a specified time precedingthe at least one detected stop trigger.

A video-data chapter segmentation computer system includes a processorand a memory. The memory includes software instructions adapted toenable the computer system to perform the steps of monitoring for atleast one external start trigger, and responsive to detection of atleast one of the at least one external start trigger, creating a chapterstart point at a point in the video data corresponding to a specifiedtime preceding the at least one detected external start trigger. Thesoftware instructions are further adapted to enable the computer systemto perform the steps of initiating recording of the video data beginningat the point in the video data, monitoring for at least one stoptrigger, and responsive to detection of at least one of the at least onestop trigger, creating a chapter stop point at a point in the datacorresponding to a specified time preceding the at least one detectedstop trigger.

A data-encoding system includes a source of unencoded data, and a firstencoder interoperably coupled to the source, wherein the first encoderis adapted to receive the unencoded data, encode the unencoded data, andoutput encoded data at a first data rate. The data encoding systemfurther includes a second encoder interoperably coupled to the source,wherein the second encoder is adapted to receive the unencoded data,encode the unencoded data, and output encoded data at a second data ratein which the second data rate exceeds the first data rate.

A data-encoding method includes a first encoder interoperably coupled toa source of unencoded data receiving the unencoded data, encoding theunencoded data, and outputting encoded data at a first data rate. Themethod further includes a second encoder interoperably coupled to thesource receiving the unencoded data, encoding the unencoded data, andoutputting encoded data at a second data rate, wherein the second datarate exceeds the first data rate.

A data-overflow-handling method includes storing at least one ofcaptured audio data, video data, and metadata to a first directory of anon-removable data storage medium, and determining whether an event isbeing recorded. The method further includes responsive to adetermination that an event is being recorded, storing an image of thestored at least one of captured audio data, video data, and metadata toa second directory of the non-removable data storage medium. The methodstill further includes determining whether a predefined capacitythreshold relative to a removable data storage medium has been exceeded,and responsive to a determination that the predefined capacity thresholdhas been exceeded, creating a third directory of the non-removable datastorage medium. The method still further includes determining whetherdata in the second directory of the non-removable storage medium has notbeen stored to the removable data storage medium, and responsive to adetermination that data in the second directory of the non-removablestorage medium has not been stored to the removable data storage medium,storing any unstored data in the second directory to the removable datastorage medium. The method further includes determining whether thesecond directory contains finalization files, and responsive to adetermination that the second directory contains finalization files,finalizing the removable storage medium and providing a prompt to insertanother removable storage medium. The method still further includesresponsive to a determination that the second directory contains nofinalization files, returning to the step of determining whether data inthe second directory of the non-removable storage medium has not beenstored to the removable data storage medium.

A data-overflow-handling computer system includes a processor and amemory. The memory includes software instructions adapted to enable thecomputer system to perform the steps of storing at least one of capturedaudio data, video data, and metadata to a first directory of anon-removable data storage medium, determining whether an event is beingrecorded, and responsive to a determination that an event is beingrecorded, storing an image of the stored at least one of captured audiodata, video data, and metadata to a second directory of thenon-removable data storage medium. The memory further includes softwareinstructions adapted to enable the computer system to perform the stepsof determining whether a predefined capacity threshold relative to aremovable data storage medium has been exceeded, and responsive to adetermination that the predefined capacity threshold has been exceeded,creating a third directory of the non-removable data storage medium. Thememory further includes software instructions adapted to enable thecomputer system to perform the steps of determining whether data in thesecond directory of the non-removable storage medium has not been storedto the removable data storage medium, and responsive to a determinationthat data in the second directory of the non-removable storage mediumhas not been stored to the removable data storage medium, storing anyunstored data in the second directory to the removable data storagemedium. The memory further includes software instructions adapted toenable the computer system to perform the steps of determining whetherthe second directory contains finalization files, and responsive to adetermination that the second directory contains finalization files,finalizing the removable storage medium and providing a prompt to insertanother removable storage medium. The memory still further includessoftware instructions adapted to enable the computer system to performthe step of responsive to a determination that the second directorycontains no finalization files, returning to the step of determiningwhether data in the second directory of the non-removable storage mediumhas not been stored to the removable data storage medium.

A method for archiving data includes receiving data, storing the data ona first data storage medium, and selecting a portion of the data. Themethod further includes determining if at least one environmental factorindicates that environmental conditions are acceptable for storing theselected portion of the data on a second data storage medium. The methodstill further includes responsive to a determination that the at leastone environmental factor indicates that environmental conditions areacceptable, storing the selected portion of the data on the second datastorage medium.

A computer system for archiving data includes a processor and a memory.The memory includes software instructions adapted to enable the computersystem to perform the steps of receiving data, storing the data on afirst data storage medium, and selecting a portion of the data. Thememory further software instructions adapted to enable the computersystem to perform the steps of determining if at least one environmentalfactor indicates that environmental conditions are acceptable forstoring the selected portion of the data on a second data storagemedium, and responsive to a determination that the at least oneenvironmental factor indicates that environmental conditions areacceptable, storing the selected portion of the data on the second datastorage medium.

A data security method includes performing a checksum on data containedon a removable data storage medium, and storing the checksum on theremovable data storage medium in at least one of an encrypted and ahidden form. The method further includes storing a unique serial numberpertaining to the removable storage medium to the removable storagemedium, and storing a checksum and a corresponding unique serial numberof a plurality of previous removable storage media to the removablestorage medium.

A data security computer system includes a processor and a memory. Thememory includes software instructions adapted to enable the computersystem to perform the steps of performing a checksum on data containedon a removable data storage medium, and storing the checksum on theremovable data storage medium in at least one of an encrypted and ahidden form. The memory further includes software instructions adaptedto enable the computer system to perform the steps of storing a uniqueserial number pertaining to the removable storage medium to theremovable storage medium, and storing a checksum and a correspondingunique serial number of a plurality of previous removable storage mediato the removable storage medium.

The above summary of the invention is not intended to represent eachembodiment or every aspect of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the method and apparatus of the presentinvention may be obtained by reference to the following DetailedDescription when taken in conjunction with the accompanying Drawingswherein:

FIG. 1 is a block diagram of an in-vehicle system for recording video,audio, and data in accordance with principles of the present invention;

FIG. 2 is a procedure for opportunistic archiving without error checkingin accordance with principles of the present invention;

FIG. 3 is a procedure for opportunistic archiving with optional errorchecking in accordance with principles of the present invention;

FIG. 4 is a procedure for automatic DVD-video chapter segmentation byexternal triggers in accordance with principles of the presentinvention;

FIG. 5 is a procedure for parallel high and low bit-rate encoding withpost even bit rate selection in accordance with principles of thepresent invention;

FIG. 6 is a perspective and side view of an embodiment of a drivesuspension system in accordance with principles of the presentinvention; and

FIG. 7 is a procedure for automatic DVD-video disc record overflowhandling in accordance with principles of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, a block diagram of an in-vehicle system forrecording video, audio, and data in accordance with an embodiment of thepresent invention is illustrated. In the system of FIG. 1, a first videodecoder 10 a and a second video decoder 10 b each include a plurality ofrespective video inputs 15 a, 15 b for receiving analog video signalsfrom one or more video sources, such as, for example, a video camera. Inthe embodiment of the present invention illustrated in FIG. 1, each ofthe video decoder 10 a and 10 b receives analog video signals from afront video camera, a rear video camera, and an in-vehicle camera,although it should be understood that, in some embodiments, more orfewer cameras may be used. Each of the video decoders 10 a, 10 bprocesses the received video signals and produces respective digitalvideo signals 20 a and 20 b. The digital video signals 20 a and 20 b arethen provided to a video processor 25. The video processor 25 processesthe digital video signals 20 a and 20 b and outputs the processed videosignals to a video bus 35 as a video stream.

In an exemplary embodiment of the present invention, the video processor25 includes a video picture-over-picture (POP) field programmable gatearray (FPGA) chip that processes video from one or more sources tocombine the video from the multiple sources to be combined into a singlevideo stream. For example, two video camera feeds can be processed bythe video processor 25 for simultaneous display on the same screen as asplit screen image. The system of FIG. 1 can be further provided with aframe memory 30 associated with the video processor 25 to store videoframes during processing by the video processor 25. The video streamfrom the video bus 35 is provided to first and second audio/videoencoder integrated circuits (ICs) 40 a, 40 b. In accordance withprinciples of the present invention, the first and second video encoderICs 40 a, 40 b include circuitry adapted to encode video and audio incompliance with a Motion Picture Expert Group (MPEG) standard, such asthe MPEG-2 standard. For example the first and second video encoders 40a, 40 b can be MPEG codec ICs. However, other video-encoding standardsmay be used without departing from principles of the invention.

The system of FIG. 1 also includes an audio analog-to-digital converter45 adapted to receive analog audio signals 50 from one or more audiosources, such as microphones, and process the analog audio signals 50 toproduce a digital audio signal 55. In accordance with the embodiment ofthe present invention illustrated in FIG. 1, an analog audio signal froma wireless microphone is provided to a left channel input of the audioanalog-to-digital converter 45, an analog audio signal from a cabinmicrophone is provided to a right channel of the audio analog-to-digitalconverter 45, and the audio analog-to-digital converter 45 outputs acombined digital audio signal 55 therefrom.

The digital audio signal 55 is then provided to each of the first andsecond audio/video encoder ICs 40 a, 40 b. Each of the first and secondaudio/video encoder ICs 40 a, 40 b encodes the video stream receivedfrom the video bus 35 and the digital audio signal 55 from the audioanalog-to-digital converter 45 as respective encoded audio/video streams60 a and 60 b, such as, for example, MPEG-2 streams. In variousembodiments of the present invention, the first audio/video encoder IC40 a and the second audio/video encoder IC 40 b output representationsof the same video and audio streams that have been encoded at differentdata rates in parallel. For example, in accordance with principles ofthe present invention, the first audio/video encoder IC 40 a outputs ahigh-bit-rate encoded stream 60 a (e.g., 6.0 Mbps), while the secondaudio/video encoder IC 40 b outputs a low-bit-rate encoded stream 60 b(e.g., 1.0 Mbps) representation of the same audio and video signals. Thelow-bit-rate stream can be obtained, for example, by reducing at leastone of the video resolution and the frame rate. The system of FIG. 1 canbe further provided with first and second coded memory 65 a, 65 bassociated with each of the first and second audio/video encoder ICs 40a, 40 b, respectively, for use by the first and second audio/videoencoder ICs 40 a, 40 b as memory storage during encoding operations.

The resolution, bit-rate, and frame rate of both the low-bit-rate streamand the high-bit-rate stream can be set based on a record lengthselection made in a setup menu. Some example combinations are shown inTable 1:

TABLE 1 Resolution Var. Bit rate Frame Rate Record Length 720 × 480 5-6Mbps 30 fps 2 hrs 480 × 480 2.0 Mbps 30 fps 4 hrs 352 × 480 1.5 Mbps 30fps 6 hrs 352 × 480 1.1 Mbps 30 fps 8 hrs

Each of the first encoded stream 60 a and the second encoded stream 60 bare then provided to a system FPGA 70. The system FPGA 70 provides thefirst encoded stream 60 a and the second encoded stream 60 b over an IDEbus 75 to a hard drive 80. The system of FIG. 1 can further include abuffer memory 90 associated with the system FPGA 70 to buffer databefore it is written to the hard drive 80. The first encoded stream 60 aand the second encoded stream 60 b are each buffered and written to thehard drive 80. As a result, two versions of the same video and audiosource, for example, a high-bit-rate encoded and a low-bit-rate encodedversion, are buffered and written to the hard drive 80 for subsequentprocessing. After a predetermined time period has elapsed and/or after aparticular event has occurred, the encoded video and audio data may besent over the IDE bus 75 from the hard drive 80 to a DVD read/write (RW)drive 85 for archiving to a DVD disc. In accordance with an embodimentof the present invention, the encoded video and audio data is written tothe DVD disc so that the DVD disc is formatted as a standard DVD videodisc playable in a standalone (i.e., non-PC based) DVD player. The harddrive 80 is described as an example of a non-removable data storagemedium such as typically found in personal computers. A DVD disc isdescribed as an example of a removable data storage medium. Otherexamples of removable data storage media include floppy discs, and flashmemory drives.

The system of FIG. 1 further includes a microcontroller 90 thatfunctions to control the various components as well as the overalloperation of the system of FIG. 1. Flash memory 100 and dynamic RAM 105may further be connected to the microcontroller 90 via a system bus 95.The flash memory 100 may function to store firmware for use by themicrocontroller 90, and the dynamic RAM 105 may be used by themicrocontroller 90 as temporary storage. In accordance with principlesof the present invention, the firmware within the flash memory 100 canbe upgraded, for example, by inserting a disc including updated firmwareinto the DVD RW drive 85.

The microcontroller 90 is further provided with a data input 110 forreceiving metadata including externally-measured data. Examples ofmetadata that can be provided to the data input 110 include GlobalPositioning System (GPS) coordinates, GPS calculated patrol speed,vehicle speed sensor (VSS) calculated patrol speed, radar measuredpatrol speed, radar target speed, accelerometer X, Y, and Z values,braking status, emergency lights status, siren status, system boardtemperature, drive door opening and closing logging, power up and powerdown logging, and DVD disc ejection and insertion logging. The metadatais provided by the microcontroller 90 to the system FPGA 70, whichfurther transmits the metadata to the hard drive 80, where it is writtento a metadata log file in association with the encoded audio and videodata. Accordingly, a particular item of metadata can be directly linkedto the audio and video segment obtained at the time that the metadataitem was measured.

In addition, a subset of the metadata is included in the encoded audioand video data so that it is available for viewing in parallel with theaudio and video during playback. In accordance with an embodiment of thepresent invention, the subset of the metadata is included in one or moreclosed-captioning fields of an MPEG-2 encoded DVD disc. An advantageprovided by including the subset of the metadata in a closed-captioningfield is that the visibility of the metadata information can beselectively toggled by a viewer of the audio and video. Anotheradvantage provided by including the subset of the metadata in aclosed-captioning field is that the information in the closed-captioningfield is a text overlay that does not effect the encoding of theunderlying video; thus, the underlying video is not degraded by theinclusion of the metadata. Examples of metadata that may be included inthe closed-captioning field include time, date, frame counter, vehicleID, GPS longitude and latitude, vehicle speed (from VSS signal), radartarget speed, radar patrol car speed, remote microphone activeindicator, emergency lights active indicator, siren active indicator,braking in progress indicator, and camera ID and zoom level. In stillanother embodiment of the present invention, the subset of metadata mayby provided in a subtitle field.

The system of FIG. 1 further allows for playback of encoded audio andvideo stored on the hard drive 80 and a disc in the DVD RW drive 85. Toaccomplish playback, the system of FIG. 1 further includes a DVD decoder115 that receives encoded audio and video from either the hard drive 80or the DVD RW drive 85 via a playback bus. The DVD decoder 115 decodesthe video into a video output signal 120 and decodes the audio into adigital audio signal 125. The digital audio signal 125 is provided to adigital-to-audio converter 130 that converts the digital audio signal toan analog audio signal 135. A DVD/on-screen display (OSD) memory 140 mayfurther be provided for use by the DVD decoder 115 as temporary storageduring decoding.

The system of FIG. 1 may also be provided with an Ethernet interface 145that allows for communication between either a wired or wirelessEthernet-connected device and the microcontroller 90. The Ethernetinterface 145 may be used, for example, for transmitting encoded audioand video, as well as associated metadata, to a central office. TheEthernet port can also be used for uploading new firmware files, and forpopulating user settings as configured on a laptop computer attached tothe invention. Specific identifiers shown in FIG. 1 for variouscomponents illustrated therein are for illustrative purposes. Theseidentifiers will be understood by those having skill in the art to bemerely examples of components that could be employed in the system showntherein. Other commercially available components could be employedwithout departing from the principles of the invention.

Event Based Recording

In various embodiments of the present invention, recording of video,audio, and metadata is event-based. In these embodiments, the systemonly records when a triggering event has occurred, for example, when theuser turns on the emergency lights, siren, the onboard accelerometerssense a vehicle crash, or when the user manually hits a record button.Upon occurrence of the event, the beginning of a recorded event ismarked. Other examples of an event that initiates recording can be, forexample, a traffic stop, a chase, a domestic call, or pulling into adriveway. The recording of the event continues until a stop point isdetermined. In at least one embodiment of the present invention, thestop point is determined when the user hits a stop button. The systemmay also include an automatic stop event that allows the system toautomatically stop recording at a predetermined time after all startrecord triggers have been turned off (e.g., the lights and siren are offand the wireless microphone is off), but the user has forgotten to hitthe stop button. If the system detects that that condition has occurredbased on user settings, it can decide to enter a stop flag and stoprecording the event.

In at least one embodiment of the present invention, when the system isturned on, two data streams (i.e., a high bit-rate stream and a lowbit-rate stream) as well as metadata are recorded to the hard drive 80.The metadata may include, for example, the status of the brake lights,status of the emergency lights and siren, GPS coordinates, the vehicle'sspeed, data from an interface from the police radar system, etc. Themetadata and the high and low bit-rate streams are time-stamped andsynchronized. During recording to a DVD disc, the video and/or audio ofevents, as well as the metadata are recorded to the DVD disc.

The system may also use vehicle speed as a recording trigger where thesystem can initiate the recording of an event if the patrol car exceedsa preset speed. For example, a department supervisor can decide that ifan officer ever goes in excess of 110 miles an hour, the system shouldbegin recording an event to the hard drive 80 or the DVD drive 85. A newevent begins automatically and the officer has no control over therecording of the event. Likewise, organizations outside of lawenforcement may utilize threshold criteria for initiatingself-activating monitoring of persons or conditions.

Opportunistic Archiving

The automobile environment is subject to demanding environmentalconditions for the operation of electronic equipment. Recording onto arewriteable DVD in an automobile environment is particularly subject tothese conditions. A system in accordance with principles the presentinvention has a drive suspension system in place. The system monitorsshock and vibration in x, y, and z axes using accelerometers. The systemmay also monitor the vehicle speed by one or more of three methods. Thesystem can monitor vehicle speed through the VSS signal. If an optionalGPS subsystem is included in the system, the system can get speedcoordinates from the GPS data. If the system is interfaced to a radarsystem and the radar is operating in moving mode, the system can getvehicle speed from the radar. In various embodiments of the presentinvention, an opportunistic archiving algorithm is used that providesparameters and steering as to when the system should burn to the DVDdrive 85. Using shock and vibration measurements, the opportunisticarchiving algorithm is adapted to ensure that data is not written to theDVD disc until environmental conditions are acceptable for doing so.

Referring now to FIG. 2, a procedure for opportunistic archiving withouterror checking in accordance with principles of the present invention isillustrated. In step 205, background recording of data including, forexample, audio data, video data, and metadata, is initiated. Inbackground recording, an encoded stream, and optionally associatedmetadata, is continuously written to the hard drive 80. Thus, referringagain to FIGS. 1 and 2, during background recording, the first encodedstream 60 a and the second encoded stream 60 b, and optionallyassociated metadata, are continuously written to the hard drive 80.Background recording of audio, video, and metadata is typicallyperformed in one minute segments, although it should be understood thatother segment lengths may be used. After initiation of backgroundrecording (step 205), the data is buffered in RAM (step 210) and thenwritten to the hard drive 80 (step 215). A determination is then maderegarding whether any record triggers are active (step 217). If adetermination is made that no active record triggers exist (step 220),background recording is continued (step 225) and the procedure returnsto step 205.

If a determination is made that a record trigger is active (step 230),the data to be archived on the DVD is selected (step 235). The range ofdata to be archived includes selected time periods before and afterevent start and stop points. For example, the system can be configuredto archive a range of data that extends from ten minutes prior to thestart point and ten minutes after the stop point. At step 240, averification of environmental factors is performed to insure thatenvironmental conditions are acceptable for recording data to the DVDdisc. The environmental factors can include, for example, temperature,shock, and vibration measurements. If the environmental factors aredetermined to exceed DVD drive limits (step 245), better environmentalconditions are waited for via use of, for example, a timer (step 250),and the procedure returns to step 240. Steps 240-255 can becharacterized collectively as opportunistic-archiving steps.

If the environmental factors are determined to be within predeterminedlimits (step 255), burning of a sector of data to the DVD disc isinitiated (step 260). During the burn cycle, accelerometers aremonitored to determine whether any G-spikes exceed tolerable limits(step 265). An example of a tolerable limit for burning of data to a DVDis less than 0.3 G. If it is determined that a G-spike occurred duringthe burn cycle that is above tolerable limits (step 270), a decision ismade to rewrite the sector in question (step 275) and the procedurereturns to step 260. If it is determined that no G-spikes occurredduring the burn cycle that are above the tolerable limits (step 280),the procedure continues to the next sector to be burned (step 285) andthen returns to step 205. Steps 260-285 can be characterizedcollectively as reactive correction steps.

Referring now to FIG. 3, a procedure for opportunistic archiving withoptional error checking in accordance with principles of the presentinvention is illustrated. In step 305, background recording of dataincluding, for example, audio data, video data, and metadata, isinitiated. In background recording, an encoded stream, and optionallyassociated metadata, is continuously written to the hard drive 80. Thus,referring again to FIGS. 1 and 3, during background recording, the firstencoded stream 60 a and the second encoded stream 60 b, and optionallyassociated metadata, are continuously written to the hard drive 80.Background recording of audio data, video data, and metadata istypically performed in one minute segments, although it should beunderstood that other segment lengths may be used. After initiation ofbackground recording (step 305), the data is buffered in RAM (step 310)and then written to the hard drive 80 (step 315). A determination isthen made regarding whether any record triggers are active (step 317).If a determination is made that no active record triggers exist (step320), background recording is continued (step 325) and the procedurereturns to step 305.

If a determination is made that a record trigger is active (step 330),the data to be archived on the DVD is selected (step 335). The range ofdata to be archived includes selected time periods before and afterevent start and stop points. For example, the system can be configuredto archive a range of data that extends from ten minutes prior to thestart point and ten minutes after the stop point. At step 340, averification of environmental factors is performed in order to insurethat environmental conditions are acceptable for recording data to theDVD disc. The environmental factors can include, for example,temperature, shock, and vibration measurements. If the environmentalfactors are determined to exceed DVD drive limits (step 345), betterenvironmental conditions are waited for via use of, for example, a timer(step 350), and the procedure returns to step 340. Steps 340-355 can becharacterized collectively as opportunistic archiving steps.

If the environmental factors are determined to be within predeterminedlimits (step 355), burning a sector of data to the DVD disc is initiated(step 360). At step 365, a checksum is calculate for the sector fromhard drive data. The burned sector is then read from the DVD disc (step370), and a checksum is calculated from the sector read from the DVD(step 375). The checksum obtained from hard drive data and the checksumobtained from the burned DVD sector are compared and, if the checksumsdo not match, the sector is rewritten (step 380) and the procedurereturns to step 360. If the checksums match, the archiving procedurereturns to step 305. Steps 360-385 can be characterized collectively asDVD burn error correction steps.

In various embodiments, an opportunistic archiving algorithm may be usedthat also considers, in addition to environmental factors, how much datathe system needs to archive to the DVD disc. For example, if the systemstarts off in the morning and there have been no events and no startflags, the system is operating with zero unburned events. However, if,for example, the user gets into a high-speed chase that lasts for threehours and the system has not detected a stop trigger, the system hasrecorded three hours of unburned data to the hard drive 80. In thissituation, the system could lower the environmental limits, at step 255or 355 for example, in order to archive the large amount of accumulateddata to the DVD disc. Environmental conditions, including a speedfactor, may also be considered. The system may consider whether thevehicle is driving along at a high rate of speed (e.g., hundred miles anhour) or if it is stopped. The algorithm may also consider accumulatedshock and vibration.

The algorithm processing starts with the calculation of how much data ispresent and comes up with a numerical value. And then the processorusing the algorithm comes up with a numerical value for how conducivethe environment is to DVD burning. The processor using the algorithmsubtracts the environment number from the unburned data number and comesup with a value. If the value is positive, the need to burn data isgreater than how bad the environmental conditions are. If the algorithmdefines a negative number, the unburned data does not outweigh how badthe environmental conditions are.

If the environmental conditions are very poor, the system does notrecord anything. Instead, the system just waits and monitors for a whileand checks the environmental conditions again. If the speed factor iszero (i.e., the car is stopped), that is preferably an automatic burndecision. Condition one is no speed, which is preferably an automaticdecision to burn anything on the hard drive 80 that needs to be burned.Condition number two is unacceptable environmental conditions underwhich the system does not burn anything. Condition number three issomewhere in between, in which the system has some unburned event data,the car is moving, and determinations are made regarding how bad theconditions are, how much does the need to burn data outweigh theenvironmental conditions that the system detects.

The hard drive 80 of the system preferably has a accelerometer to detectphysical shocks. When the hard drive 80 detects an unacceptable shock,the system goes back and recopies the last section. An error is assumed,so the last DVD section is overwritten. The hard drive 80 may be mountedon a vibration shock mount as well. In various embodiments, the DVDdrive 85 can also include an accelerometer to detect physical shocks.Hard drives typically have a 200 g shock tolerance whereas DVD drivestypically have a 0.5 g shock tolerance.

An illustrative opportunistic archiving algorithm could utilize thefollowing equation:

(Buffer Amount)−[(Speed Factor)+(Shock Factor)+(VibrationFactor)]=Archive Threshold

where

Buffer Amount=Size of Data Buffer

Speed Factor=Accumulated Vehicle Speed From Recent History

Shock Factor=Peak Shock in Recent History

Vibration Factor=Accumulated Vibration From Recent History

If the Archive Threshold is exceeded, the need to burn data overridesthe environmental conditions. If the Archive Threshold is not exceeded,the amount of unburned data does not override the environmentalconditions.

Automatic Chapter Segmentation by Event Markers

In various embodiments of the present invention, the system may beadapted to automatically divide the video into separate navigablechapters to make location of a specific point or event easier duringplayback, such that each chapter of the DVD disc contains the data fromone event. This process eliminates the need to fast forward or rewindthe media to search for a specific traffic stop or event. The start ofan event period is determined by monitoring metadata from variousdevices, such as external emergency lights, emergency siren, wirelessmicrophone activation, extreme shock data from accelerometersindicating, for example, a collision or panic braking, an elapsed timeperiod, etc. The start of an event period can also be determined by anoperator pressing a RECORD key on a control panel.

The end of an event is determined by the operator pressing a STOP key onthe control panel or by the passage of a predetermined period of timeafter any triggering device is turned off or is inactive. In variousembodiments, when the system is turned on, all video data, audio data,and metadata is continuously written to the hard drive 80, and onlyevent data is written to the DVD disc. The system is able toautomatically include video and audio data that occurred prior to thestart of the event period or after the end of an event period by movingevent start and end flags based on rules determined by user settings.For example, a setting in a user-interface menu can be used to determinehow much data to include in the DVD chapter before and after the eventmarkers.

Referring now to FIG. 4, a procedure for automatic DVD-video chaptersegmentation by external triggers is illustrated. In step 405,background recording of data including audio, video, and metadata isinitiated. In various embodiments of the present invention, backgroundrecording of audio, video, and metadata is performed in one-minutesegments, although it should be understood that other segment lengthsmay be used. At step 410, external record triggers are monitored for theoccurrence of one or more triggering events. If a record trigger is notdetected (step 415), the procedure returns to step 405.

If a record trigger is detected (step 420), a new chapter start point isinitiated (step 425) that includes a specified number of minutes of datafrom before the event start point to the beginning of the chapter. Atstep 430, burning of the data from the event period to the DVD isstarted. At step 435, monitoring of stop triggers is performed. The stoptriggers may be either generated by a timer or user-initiated. If a stoptrigger is not detected (step 440), event recording is continued (step445), and the procedure returns to step 430. If a stop trigger isdetected (step 450), a chapter stop point is determined, which stepincludes a specified number of minutes of data from after the event stoppoint being added to the end of the chapter (step 455). Next, the DVDchapter menu is built (step 460), a video frame from the event isselected for use as a selectable chapter icon (step 465), and atime/date stamp from the chapter stop point is used as part of thechapter name/number (step 470). Next, the DVD chapter is closed out(step 475), and the procedure returns to step 405.

Parallel High and Low Bit-Rate Encoding

In order to provide users with the ability to archive as many hours ofvideo and audio data on to a single DVD disc, while still providingmaximum video quality for important events, various embodiments of thepresent invention provide for encoding multiple versions of the samevideo and audio source in parallel. The system encodes both a highbit-rate stream and a lower bit-rate stream. Both streams are bufferedand written to the hard drive 80.

The rules for archiving event data to the DVD disc can be determined byuser settings. During typical operation, the system will automaticallytransfer the lower bit-rate video stream to the DVD disc based on eventmarkers. Should the system capture some video or audio footage that theuser deems to be important, the user can transfer the high bit-rateversion to the DVD disc from data on the hard drive 80. This processallows users to make extended-length recordings without having tosacrifice audio and video quality of important events.

A user may choose high or low quality video after an event has occurred.The system by default archives events to the DVD that are low quality.After the recording has been made, if something that was important hasoccurred, the user can easily go back and set new start and stop flags.A section of video may be chosen, whether it was included in theoriginal event or not, a new chapter added to the DVD, and a highresolution version of the video can be chosen to be burned to DVD. Afterthe fact, a user can choose to grab any video from the hard drive 80 andmake new chapters on the DVD. The new chapters can be based on the sameevent or on multiple events or non-events, and then a user could choosehigh or low resolution.

Referring now to FIG. 5, a procedure for high and low bit-rate encodingwith post-event bit-rate selection in accordance with principles of thepresent invention is illustrated. In various embodiments of the presentinvention, the high and low bit-rate encoding occurs in parallel. Atstep 505, a raw video stream, such as a BT656 stream, is split intofirst and second streams that are identical to each other. The firststream is provided to a first video encoder 40 a, which encodes thestream at a low bit-rate to be used for normal recording (step 510). Thelow bit-rate stream can be optionally written to a temporary storagearea, such as a hard drive 80, Flash RAM, RAM, or other storage media(step 515). The second stream is provided to a second video encoder 40b, which encodes the stream at a high bit rate to be used as a backupfor important events (step 520). The data of the high bit-rate stream isthen written to a circular buffer (step 525), which is acontinuously-overwritten data buffer on a hard drive 80, Flash RAM, RAM,or other storage media. If no important events occur while the highbit-rate data is in the circular buffer (step 530), new high bit-ratedata overwrites old data in the circular buffer (step 535).

If an operator deems a time period from the data buffer to be important(step 540), the system takes the high-bit-rate data from the importanttime period (step 545) selected by the operator. At step 550, thelow-bit-rate data and the selected portion of the high-bit-rate data arewritten to storage media, such as a DVD disc, hard drive, flash memory,etc. (step 550). In various embodiments, the step 550 of writing thelow-bit-rate data to the storage media can include opportunisticarchiving such as that described with respect to FIG. 2 and FIG. 3. Invarious embodiment of the present invention, step 515 of writing thelow-bit-rate stream to a temporary storage can be omitted, and thelow-bit-rate stream can be written directly to the storage media in step550. In other embodiments of the present invention, the temporarystorage for the low-bit-rate data and the circular buffer for thehigh-bit-rate data are the same hard drive, and the storage media forthe low-bit-rate data and the selected portion of the high-bit-rate dataare a DVD disc.

Record after-the-Fact

Recording after-the-fact permits manual chapter event creation to beperformed. If a user wants to go in after the fact and copy some videothat wasn't marked as an event, the user can go back and manually put ina new start and stop point. The system will automatically grab thatsection of video and feed it to the DVD drive 85 and make a new chapter.The common use of that feature will be by, for example, internal affairsin order to investigate some alleged misconduct. Of course, embodimentsof the system may be applied to areas outside of the area of lawenforcement, and then the conduct referred to may be an officer oranother party in an organization utilizing the methods and systems ofthe present invention.

Drive Suspension System

A drive suspension system in accordance with principles of the presentinvention permits isolation of the DVD drive from environmentalconditions that could impair DVD burning. Different suspension systemsmay be used in different versions of the system. One version of thesystem as currently envisioned is entirely overhead-console mounted.Another version of the system is a multi-piece unit (e.g., two) that maybe used when there is not room to mount the overhead console-mountedversion. In the second version, the user can, for example, put therecording unit underneath the seat and the display and control panel ona stalk near the radio console area. Although packaging for the drivesuspension system is different on the two versions discussed, theunderlying principles are analogous and other versions are possiblewithout departing from principles of the present invention.

Referring now to FIG. 6, a perspective and side elevational view of anembodiment of a drive suspension system in accordance with an embodimentof the present invention are illustrated. In FIG. 6, a DVD recorderdrive 605 slides into a drive chassis 610. The drive suspension systemincludes a momentum mass in the form of a heavy steel chassis weight615. The assembly including the DVD recorder drive 605, the drivechassis 610, and the chassis weight 615 is suspended inside an assemblyshield area 620 by expansion elements, such as, for example, assemblysprings 625. On the chassis 610, four pins 635 insert into fourvibrational-energy-absorption elements, such as, for example,silicon-oil-filled sack dampers 630. A hole inside the particular dampershown in FIG. 6 is provided for the pins 635 from the chassis 610 tomeet into. The four silicon-oil-filled sack dampers 630 serve tostabilize the floating mechanism, provide heavy damping characteristics,and reduce the resonance frequency. The chassis weight 615 providesmomentum and also serves to help reduce the resonance frequency. In atypical embodiment, there is about one-half inch of suspension travel inevery direction.

In the under-seat version of the system, a spring orientation pivot 640is used to permit horizontal mounting or vertical mounting (e.g., on theside of a cage) or mounting on a stalk or on a center console. If thesystem is mounted flat, the springs are mounted in an upwardorientation. However, if the user turns the orientation such that thedrive is pointing upward and gravity is trying to pull the drive in adifferent direction, the spring may be pivoted so that the spring isable to handle the gravity load in that direction.

Automatic DVD-Video Disc Record Overflow Handling

Various embodiments of the invention provide a method to seamlesslyallow a user to record data onto the DVD disc to the disc's capacity,yet continue to capture and prepare additional data intended to beburned onto another DVD disc. With previous in-vehicle recordingsystems, there was a risk of running out of media (e.g., DVD) spaceduring the middle of a patrol officer's shift. Since the media isconsidered evidentiary in nature, many law enforcement agencies limitaccess to the media, and do not provide the officer with a second pieceof media. Thus, when the media became full, it would necessitate a tripback to the police station to replace the media with blank media.Automatic DVD-Video disc record overflow handling in accordance withprinciples of the invention serves to eliminate the need for an officerto return to the police station to replace media during a shift. Theofficer may continue recording even after the DVD media is at capacity.In a typical case, the system finalizes a first DVD and automaticallyprepares unburned data for an additional DVD. When new media (e.g., DVD)is inserted into the drive, the unburned data is automaticallytransferred onto the new media.

Referring now to FIG. 7, a procedure for automatic DVD-video disc recordoverflow handling is illustrated. At step 705, video, audio, and datafrom vehicle mounted cameras, microphones, and sensors is captured. Atstep 710, video, audio, and data is continuously written onto a harddrive 80. Next, a determination is made regarding whether the system isin event-record mode (step 715). If the system is not in event-recordmode, the procedure (step 720) returns to step 705. Steps 705-720 can becharacterized collectively as a data-capture process.

If it is determined that the system is in event-record mode (step 725),the procedure continues to step 730, at which step data is written intoa DVD image working directory on the hard drive 80. At step 735, adetermination is made regarding whether the working directory is closeto reaching the size limit of the DVD disc. If it is determined that theworking directory is not close to reaching the size limit of the DVDdisc (step 740), the procedure returns to step 715. If it is determinedthat the working directory is close to reaching the size limit of theDVD disc, a DVD chapter-stop point is initiated and a DVD chapter menuis built (step 745). Next, all remaining files for the DVD-video imageare closed out (step 750), the current working directory is saved (step755), and a new working directory is created (step 760). The procedurethen returns to step 715. Steps 730-760 can be characterizedcollectively as DVD image preparation steps.

From step 730, an execution proceeds also to step 765. At step 765,un-burned data in the working directory is looked for. Next, adetermination is made regarding whether there is un-burned data in theworking directory (step 770). If there is no un-burned data in theworking directory (step 775), the process returns to step 765. If thereis unburned data in the working directory, DVD-video data from theworking directory is transferred on to the DVD-video disc (step 780). Atstep 785, a determination is made regarding whether the workingdirectory contains finalized files. If the working directory does notcontain finalized files (step 787), the procedure returns to step 765.If the working directory contains finalized files, the DVD is finalized(step 790). At step 795, the user is prompted to replace the current DVDwith a blank DVD. At step 796, a determination is made regarding if theuser has loaded a blank DVD. If the user has not loaded a blank DVD(step 797), the procedure returns to step 795. If the user has loaded ablank DVD, a check is made for a new DVD working directory (step 798).The procedure then returns to step 765. Steps 765-798 can becharacterized collectively as DVD burning process steps.

Automatic DVD Disc-Image Back-Up

In various embodiments, the system's hard drive 80 is formatted with aseparate partition that is reserved for making mirror images of DVDdiscs. A typical DVD RW disc is 4.7 GB. As the system is creating a DVDdisc, the system makes an exact duplicate of the entire disc on the harddrive 80 in a separate partition. An administrator or user can selecthow many back-up copies of DVDs the system retains.

As the user continues to create new DVDs, the oldest hard-drive backupwill be overwritten; thus, if the user selected three back-up images, bythe time the user creates the fourth DVD, the oldest one is beingoverwritten with a mirror image of the number four disc. Using thisfeature, if an original DVD is lost, unreadable, or intentionallydestroyed, a supervisor can go back and create an exact copy of the sameDVD disc.

Video Data Security

Since the system's video files are typically in MPEG-2 format, the filescould conceivably be manipulated using video-editing tools. Inlitigation, attorneys could attempt bring into question the authenticityof the MPEG files, suggesting that they could be exported, manipulated,and then re-inserted onto the disc. The system thus uses checksums insome embodiments to ensure that the files have not been manipulated oredited.

First Level of Security—the Self-Verifying Checksum Result

When the system is ready to close a DVD disc (e.g., just prior to discejection), the system performs a checksum calculation on the disccontents and writes that result into a hidden and/or encrypted filesaved on the DVD disc. By using a video utility, the DVD disc can beanalyzed to see if a checksum result from the disc's contents matchesthe result of the hidden (and/or encrypted) checksum result on that DVDdisc. This process verifies that the disc content matches the checksumfile.

Second Level of Security—System Verification of the Hidden (orEncrypted) Checksum Files

The system also provides a method to verify that the checksum file thatis hidden on a DVD disc has not been recreated to match a manipulateddisc. This is done by comparing subsequently-recorded DVD discs (e.g.,discs recorded using the same system) to the DVD disc in question. Thesystem automatically generates a unique disc serial number for each DVDdisc it records. This serial number is written onto the DVD disc and isalso saved into a log file in the system's non-volatile memory. When aDVD disc is closed, the checksum result of that DVD disc is also writtento the log file in the system's non-volatile memory.

The log file preferably contains the serial number and checksum resultof every DVD disc that that specific system has authored. The entirecontents of the log files that are stored on the system's non-volatilememory may then be copied onto every DVD disc the system creates. EveryDVD disc created by a specific system can be used to verify the validityof a checksum result contained on any other DVD disc previously recordedby the same system.

Covert Recording Mode

In various embodiments of the present invention, the system has theability to be placed into a covert-recording mode. In this mode, thesystem has the appearance of being powered off. However, it is actuallyrecording data, such as video and audio, on the hard drive 80. Thecovert-recording mode permits events inside a patrol car to be recordedwithout a suspect being aware that he is being recorded. A recordtrigger is generated when the system is placed into covert-recordingmode. However, the system will only archive to the DVD after the systemhas been taken out of covert recording mode to prevent the DVD drivenoise from giving an indication that the system is not actually poweredoff.

In an illustrative example of placing the system into covert recordingmode, a user presses and holds a power OFF key for more than 2 seconds.A sound indicates that the unit has been placed into covert recordingmode and all lights, backlights, indicators, and displays are turnedoff. This gives the appearance to a back-seat occupant that the unit isturned off. The system automatically selects an interior camera input tobe recorded. The covert mode is ended by pressing POWER ON or a STOPkey. At that time, the system lights, backlights, indicators, anddisplays are turned on, and the video that has been marked for recordingwill be archived to the DVD disc.

Various embodiments of the invention may reside in a computer system.Here, the term “computer system” is to be understood to include at leasta memory and a processor. In general, the memory will store, at one timeor another, at least portions of an executable program code, and theprocessor will execute one or more of the instructions included in thatexecutable program code. It will be appreciated that the term“executable program code” and the term “software” mean substantially thesame thing for the purposes of this description. It is not necessary tothe practice of this invention that the memory and the processor bephysically located in the same place. That is to say, it is foreseenthat the processor and the memory might be in different physical piecesof equipment or even in geographically distinct locations.

Various embodiments of the invention may also be embodied in a computerprogram product, as will now be explained. On a practical level, thesoftware that enables the computer system to perform the operationsdescribed further below in detail, may be supplied on any one of avariety of media. Furthermore, the actual implementation of the approachand operations of the invention are actually statements written in aprogramming language. Such programming language statements, whenexecuted by a computer, cause the computer to act in accordance with theparticular content of the statements. Furthermore, the software thatenables a computer system to act in accordance with the invention may beprovided in any number of forms including, but not limited to, originalsource code, assembly code, object code, machine language, compressed orencrypted versions of the foregoing, and any and all equivalents.

One of skill in the art will appreciate that “media”, or“computer-readable media”, as used here, may include a diskette, a tape,a compact disc, an integrated circuit, a ROM, a CD, a cartridge, aremote transmission via a communications circuit, or any other similarmedium useable by computers. For example, to supply software forenabling a computer system to operate in accordance with the invention,the supplier might provide a diskette or might transmit the software insome form via satellite transmission, via a direct telephone link, orvia the Internet. Thus, the term, “computer readable medium” is intendedto include all of the foregoing and any other medium by which softwaremay be provided to a computer.

Although the enabling software might be “written on” a diskette, “storedin” an integrated circuit, or “carried over” a communications circuit,it will be appreciated that, for the purposes of this application, thecomputer usable medium will be referred to as “bearing” the software.Thus, the term “bearing” is intended to encompass the above and allequivalent ways in which software may be associated with a computerusable medium.

For the sake of simplicity, therefore, the term “program product” isthus used to refer to a computer useable medium, as defined above, whichbears in any form of software to enable a computer system to operateaccording to the above-identified invention. Thus, the invention mayalso be embodied in a program product bearing software that enables acomputer to perform management of information according to theinvention.

In the foregoing Detailed Description, it can be seen that variousfeatures may be grouped together into a single embodiment for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as reflecting an intention that the claimedembodiment(s) of the invention require more features than are expresslyrecited in each claim. Rather, as the following claims reflect,inventive subject matter lies in less than all the features of a singledisclosed embodiment. Thus, the following claims are hereby incorporatedinto the Detailed Description, with each claim standing on its own as aseparate embodiment of the invention.

1-75. (canceled)
 76. An after-the-fact video recording methodcomprising: receiving captured video data; continuously storing thevideo data on a non-removable data storage medium; recording a firstportion of the stored video data onto a removable data storage mediumduring an occurrence of a first event, the recording the first portioncomprising: monitoring for a start trigger corresponding to a start ofthe first event; responsive to detection of the start trigger, creatinga chapter start point in the video data corresponding to a specifiedtime preceding the detected start trigger; initiating recording of thestored video data beginning at the chapter start point; monitoring for astop trigger corresponding to an end of the first event; responsive todetection of the stop trigger, creating a chapter stop point in thevideo data corresponding to a specified time following the detected stoptrigger; and stopping recording of the stored video data at the chapterstop point; recording a second portion of the stored video data onto theremovable data storage medium after an occurrence of a second event, therecording the second portion comprising: responsive to receiving aninput of an event start point and an event stop point, retrieving thesecond portion of the stored video data from the non-removable storagemedium stored between the event start point and the event stop point;and recording the retrieved video data on the removable storage medium.77. The method of claim 76, wherein the specified time preceding thedetected start trigger is zero seconds.
 78. The method of claim 76,wherein the specified time following the detected stop trigger is zeroseconds.
 79. The method of claim 76, wherein the specified timepreceding the detected start trigger is a user-inputted time periodranging from zero minutes to ten minutes.
 80. The method of claim 76,wherein the specified time following the detected stop trigger is auser-inputted time period ranging from zero minutes to ten minutes. 81.The method of claim 76, wherein the step of monitoring for a stoptrigger comprises at least one of: monitoring for stop buttonactivation; and monitoring for expiration of a timer.
 82. The method ofclaim 76, further comprising: building a chapter menu; and using a framefrom the video data between the chapter start point and the chapter stopinclusive as a selectable chapter icon.
 83. The method of claim 76,wherein the step of recording the first portion of the stored video datais done simultaneously to the step of storing the video data.
 84. Themethod of claim 76, wherein the removable data storage medium is adigital video disc.
 85. An after-the-fact video recording computersystem comprising: a processor; a non-removable data storage medium; anda memory including software instructions adapted to enable the computersystem to perform the steps of: receiving captured video data;continuously storing the video data on the non-removable data storagemedium; recording a first portion of the stored video data on aremovable data storage medium at the time of an occurrence of a firstevent, the recording the first portion comprising: monitoring for astart trigger corresponding to a start of the first event; responsive todetection of the start trigger, creating a chapter start point in thevideo data corresponding to a specified time preceding the detectedstart trigger; initiating recording of the stored video data beginningat the chapter start point; monitoring for a stop trigger correspondingto an end of the first event; responsive to detection of the stoptrigger, creating a chapter stop point in the video data correspondingto a specified time following the detected stop trigger; and stoppingrecording of the stored video data at the chapter stop point; recordinga second portion of the stored video data onto the removable datastorage medium after the occurrence of a second event, the recording thesecond portion comprising: responsive to receiving an input of an eventstart point and an event stop point, retrieving the second portion ofthe stored video data from the non-removable storage medium storedbetween the event start point and the event stop point; and recordingthe retrieved video data on the removable storage medium.
 86. Thecomputer system of claim 85, wherein the specified time preceding thedetected start trigger is zero seconds.
 87. The computer system of claim85, wherein the specified time following the detected stop trigger iszero seconds.
 88. The computer system of claim 85, wherein the specifiedtime preceding the detected start trigger is a user-inputted time periodranging from zero minutes to ten minutes.
 89. The computer system ofclaim 85, wherein the specified time following the detected stop triggeris a user-inputted time period ranging from zero minutes to ten minutes.90. The computer system of claim 85, wherein the step of monitoring fora stop trigger comprises at least one of: monitoring for stop buttonactivation; and monitoring for expiration of a timer.
 91. The computersystem of claim 85, further comprising software instructions adapted toenable the computer system to perform the steps of: building a chaptermenu; and using a frame from the video data between the chapter startpoint and the chapter stop inclusive as a selectable chapter icon. 92.The computer system of claim 91, further comprising softwareinstructions adapted to enable the computer system to perform the stepof using a time and date stamp from the chapter start point in a chapteridentifier.
 93. The computer system of claim 85, the softwareinstructions further comprising software instructions adapted to enablethe computer system to simultaneously perform the steps of storing thevideo data and recording the first portion.
 94. The computer system ofclaim 85, wherein the removable data storage medium is a digital videodisc.